package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.ScrollResult;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Autowired
    private IUserService userservice;

    @Autowired
    StringRedisTemplate stringRedisTemplate;
    public Result queryBlogById(Long Id){
        Blog blog = getById(Id);
        if(blog==null){
            return Result.fail("笔记不存在！");
        }

        queryBlogUser(blog);
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userservice.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    public Result likeBlog(Long id){
        Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + id;
//        Boolean ismember = stringRedisTemplate.opsForSet().isMember(key, userId.toString());
//        if (BooleanUtil.isFalse(ismember)) {
//            boolean isSuccess = update().setSql("liked = liked + 1 ").eq("id", id).update();
//            if (isSuccess) {
//                stringRedisTemplate.opsForSet().add(key,userId.toString());
//            }
//        }else {
//            boolean isSuccess = update().setSql("liked = liked - 1 ").eq("id", id).update();
//            if (isSuccess) {
//                stringRedisTemplate.opsForSet().remove(key,userId.toString());
//            }
//        }
//        return Result.ok();

        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(score==null){
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if(isSuccess){
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else {
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5==null||top5.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        List<UserDTO> userDTOS = userservice.query()
                .in("id", ids)
                .last("ORDER BY FIELD(id," + idStr + ")").list()
                .stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(userDTOS);
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        Long userId = UserHolder.getUser().getId();
        String key = FEED_KEY + userId;
        /**
         * 按分数倒序（从大到小）返回 ZSet 中指定分数范围内的元素，并且每个元素包含其分数
         *
         * key：ZSet 对应的 Redis 键。
         * 0：分数范围的起始值，表示从分数为 0 开始。
         * max：分数范围的结束值，表示最大分数。
         * offset：从哪一个索引开始返回结果（可以理解为跳过前多少个元素）。
         * 2：每次返回多少个元素（即每次返回 2 个元素）。
         */
//        stringRedisTemplate.opsForZSet().add(key,"6",System.currentTimeMillis()); //预热redis使用
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if (typedTuples == null || typedTuples.isEmpty()) {
            return Result.ok();
        }

        ArrayList<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0l;
        int os = 1;

        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            ids.add(Long.valueOf(typedTuple.getValue()));
            // 4.2.获取分数(时间戳）
            long time = typedTuple.getScore().longValue();
            if (time == minTime) {
                os++;
            }else{
                minTime = time;
                os = 1;
            }
        }

        os = minTime == max?os:os+offset;

        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Blog blog : blogs) {
            // 5.1.查询blog有关的用户
            queryBlogUser(blog);
            // 5.2.查询blog是否被点赞
            isBlogLiked(blog);
        }

        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);
        return Result.ok(r);
    }

    private void isBlogLiked(Blog blog){
        UserDTO user = UserHolder.getUser();
        if (user==null) {
            return;
        }
        Long userId = user.getId();
        String key = "blog:liked:" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }
}
